Investigation of blood coagulation and hemophilia with a study of the hemophilias in dogs and von Willebrand disease in dogs and swine from genetic, biochemical and pathologic points of view, and the study of some of the basic reactions of platelets with plasma proteins in the development of platelet adhesion and aggregation. Specific areas of investigation include studies of: a) genetics and pathophysiology of canine hemophilia A; b) study of animal von Willebrand disease and a platelet aggregation factor in porcine and canine plasmas which are deficient in von Willebrand disease; c) studies on dogs with multiple inherited deficiencies in plasma procoagulants; d) purification and study of venom coagglutinin, an "activator" of the von Willebrand factor.